center=(2,-5) and radius =3
the general form of the equation of a circle is [tex]x^{2} +y^{2} +2gx+2fy+c=0[/tex]
in this equation [tex]x^{2} +y^{2} -4x+10y+20=0[/tex]
comparing the coefficient 2g= -4 this implies g= -2
2f=10 this implies f=5 and c=20
center=(-g, -f)= ( 2, -5)
and r=[tex]\sqrt{g^2+f^2-c}[/tex]= [tex]\sqrt{( -2)^2+5^2-20}[/tex]
we get r= 3
learn more of radius and center here https://brainly.com/question/426029
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